Typically, process cartridges which are used in electrographic apparatuses include a casing which encloses a rotatable electrographic drum and various processing components spaced peripherally around the drum. These components usually include a toner hopper having toner particles therein which form a latent image on the drum in a manner well known in the art. A cleaner housing is provided in peripherally spaced relation to the toner housing and is disposed for removing and storing the used toner particles retrieved from the drum, in a manner well known in the art, after the image has been transferred to a sheet of paper or the like. A corona assembly is provided in peripherally spaced relation to the cleaner housing and is disposed for providing a uniform charge of positive or negative polarity to the drum.
Typically, the above described process cartridge is used in an electrographic apparatus which includes a housing enclosing an optical unit for scanningly deflecting a light from a light source such as a laser onto the photosensitive drum to aid in forming the image thereon. The housing apparatus generally includes upper and lower sections which are separable to provide access therein. The housing of the apparatus also includes paper feed means for feeding sheets of paper past the drum so that the latent image on the drum may be transferred to the paper. After the image transfer function, the paper feed mechanism directs the paper out of the apparatus.
In some instances, the process cartridge does not provide access into the interior thereof which assures that if the drum, cleaner device, or corona is damaged if they have just become expended, or if the toner in the toner housing (hopper) is used up, it is necessary to discard all of the components of the casing, including the casing, so that the casing, drum, corona assembly, toner housing, and cleaner housing must be replaced as a unit.
Generally, the first of the processing components which requires attention is the toner housing since the toner particles are depleted (removed from the housing) during the like time of the process cartridge. When this occurs, as stated above, the process kit must be removed from the apparatus housing and discarded as a unit.
Generally, when such an event occurs, the remaining components which are discarded have not expired and have a considerable amount of "lifetime" remaining.
It is an object of the present invention, therefore, to provide a process cartridge for use in electrographic apparatuses which will have a longer "lifetime" than those generally now available.
It is a feature of the present invention to provide such a process cartridge with an enlarged toner capacity without the need to increase the size or change the external configuration of the casing of the process cartridge.
Another feature of the present invention is the provision of means for assuring that substantially all of the toner in the toner housing is made available for use by eliminating areas in the toner housing which inherently "trap" toner particles in the housing and thus result in unused toner being left in the toner housing which is to be discarded.
These and other objects and features of the present invention will become more readily apparent from the following description taken in conjunction with the accompanying drawings.